The present invention relates to system for chamfering the edge of an electronic card and particularly to a milling system for chamfering the edge of a card (e.g. a SIMM card) to facilitate its insertion in a socket on a board.
In the manufacturing process of electronic packages, the cards (e.g. a SIMM or DIMM card) are usually manufactured in panels of 10-12 pieces at a time and then cut into single cards. This cutting operation is usually done with a router cutting machine, i.e. a machine having a rotating blade. The sharp angles obtained with this cutting operation may cause problems when the card will be finally inserted in its socket on a board (e.g. a PC motherboard). Normally the card (e.g. a SIMM card) is pushed inside a connector to realise the electrical contacts and the connection between the card and the board. During the operation of insertion of the card, the corners rub and scratch against the socket. This friction between the materials can generate little particles (chips) from the sharp corners of the card. These particles are very dangerous because they could cause failures to the card, due to bad electrical contacts or short circuits inside the socket. FIG. 1 shows a SIMM card having a plurality of metal electric contacts 103 close to the edge 101, which is on the side to be inserted in the socket as shown by FIG. 1a. It would be advisable to have the card corners rounded off as shown in FIG. 2b to facilitate the insertion into the sockets and to avoid the friction problems caused by the sharp edges of the card (FIG. 2a).
A possible solution would be a manual milling operation. It should be immediately evident that this manual technique is very laborious and also not completely reliable, because of the human intervention. Furthermore, the interruption of the mechanical handling of the modules for the manual milling and refinement leaves open the eventuality of contamination during the waiting times and the handling of the modules.
On the other hand an automated milling operation is not easily possible, because of the precision required in order not to damage the electrical contacts close to the border.
It is an object of the present invention to provide a technique which overcomes the above drawbacks.
According to the present invention, we provide a milling system for chamfering an edge of an electronic card, the system comprising:
milling means for milling said card edge, the milling means including at least one couple of juxtaposed rotating mills, each mill having an axis of rotation forming an acute angle with the plane on which the card lies;
movable guide means for relatively positioning the milling means and the card, the guide means being coupled to said milling means and having a follower being in contact with the card edge during the chamfering operation to follow the card edge;
moving means for relatively moving the card and the milling means, the card passing through said at least one couple of mills.